High-temperature stable gate structure with metallic electrode
View Patent ↗The present invention provides a method for depositing a dielectric stack comprising forming a dielectric layer atop a substrate, the dielectric layer comprising at least oxygen and silicon atoms; forming a layer of metal atoms atop the dielectric layer within a non-oxidizing atmosphere, wherein the layer of metal atoms has a thickness of less than about 15 Å; forming an oxygen diffusion barrier atop the layer of metal atoms, wherein the non-oxidizing atmosphere is maintained; forming a gate conductor atop the oxygen diffusion barrier; and annealing the layer of metal atoms and the dielectric layer, wherein the layer of metal atoms reacts with the dielectric layer to provide a continuous metal oxide layer having a dielectric constant ranging from about 25 to about 30 and a thickness less than about 15 Å.
1. A method for depositing a stack comprising:
forming a layer atop a substrate, said layer comprising at least oxygen and silicon atoms;
forming a layer of metal atoms atop said layer within a non-oxidizing atmosphere, wherein said layer of metal atoms has a thickness of less than about 15 Å;
forming an oxygen diffusion barrier atop said layer of metal atoms, wherein said non-oxidizing atmosphere is maintained and said oxygen diffusion barrier is selected from the group consisting of a metal nitride and a metal;
forming a gate conductor atop said oxygen diffusion barrier; and
annealing said layer of metal atoms and said layer, wherein said layer of metal atoms reacts with said layer to provide a continuous metal oxide layer having a thickness less than about 15 Å.
2. The method of claim 1 further comprising depositing an interface layer of metal atoms atop said oxygen diffusion barrier prior to forming said gate conductor, wherein during said annealing said interface layer of metal atoms forms a metal interface between said gate conductor and said oxygen diffusion barrier having a contact resistance of less than about 1×10 −6 Ω·cm 2 .
3. The method of claim 1 wherein said forming said layer of metal atoms comprises chemical vapor deposition or physical vapor deposition.
4. The method of claim 1 wherein said layer of metal atoms has a thickness ranging from about 2 Å to about 10 Å.
5. The method of claim 1 wherein said layer of metal atoms has a thickness ranging from about 1 monolayer to about 5 monolayer.
6. The method of claim 1 wherein said layer of metal atoms comprises 5×10 14 atoms/cm 2 to about 1×10 16 atoms/cm 2 .
7. The method of claim 2 wherein said layer of metal atoms, said oxygen diffusion barrier and said interface layer of metal atoms are formed by in-situ deposition in a cluster tool, wherein said cluster tool comprises multiple deposition chambers, wherein said multiple deposition chambers maintain said non-oxidizing atmosphere.
8. The method of claim 1 wherein said layer of metal atoms comprises Ti.
9. The method of claim 1 wherein said oxygen diffusion barrier comprises a metal nitride selected from the group consisting of titanium nitride, tungsten nitride, and tantalum nitride.
10. The method of claim 2 wherein said interface layer of metal atoms comprises titanium, tantalum or tungsten and reacts to form said metal interface comprising metal silicide or metal nitride.
11. The method of claim 1 wherein during said annealing said layer of metal atoms fully reacts with said layer, wherein said metal atoms bond to said oxygen atoms to provide said continuous metal oxide layer in an upper portion of said layer.
12. The method of claim 11 wherein said upper portion of said layer has a depth ranging from about 5 Å to about 15 Å.
13. The method of claim 1 , further comprising:
etching to form gate regions; and
forming spacers abutting said gate regions.